Flechado literally means "struck by an arrow." It's a vivid and somewhat dramatic word that isn't used in everyday conversation, making it memorable.
In the context of the song, the artist asks, "¿Cuál será la próxima canción que deje a tu corazón flechado?" (Which will be the next song that leaves your heart smitten?). Here, it's used metaphorically to describe the powerful impact a song can have, making someone fall in love with it, much like Cupid's arrow striking a heart.
In "CUÁL?", which translates to "Which?", the artist paints a picture of a life filled with searching and ambition. He's on a quest for several things at once: success, love, and the perfect creative moment. The lyrics describe him as being "addicted to great results" and always looking to have more than he's used to, all while trying to leave "evil aside" in a "city, a collector of sins."
The central theme revolves around the question "Which one?" He wonders which street will lead him to a special woman, which exact minute will be the right one, and which look from her will make him "fly." This search for a specific person and a perfect moment is intertwined with his artistic journey, as he also asks which song will be the one to capture his listener's heart. It's a song about navigating the city, chasing big dreams with his team by his side, and hoping to find that one specific connection that will make it all worthwhile.